The present invention relates to an electric power circuit breaker of the type having a pair of main power contacts, a pair of commutation or arcing contacts, and a coil through which the current flows as it passes through the arcing contacts.
A circuit breaker of this type is disclosed, for instance, in Swiss Patent Application No. 3815/80-0. In this circuit breaker, after the main contacts have opened, the current which is to be broken commutates into a current path in which it successively flows through the coil and through the arcing contact of a first switching element. This arcing contact is designed as an arc-commutating ring and is connected to the coil by electrically conducting means. The current then flows through the arcing contact of a second switching element. This contact can move relative to the main power contact. Since the coil through which the current to be interrupted flows is provided with a ferromagnetic core, a powerful magnetic field acts on the arc which forms between the arcing contacts. This magnetic field causes the arc to rotate rapidly around the arcing contact of the first switching element. On the other hand, however, this powerful magnetic field also hinders the commutation of heavy currents from the main current path onto the coil path.